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Hi Guys,

The reason I'm asking is I got a nice dirty rusty M37 PCV in a box of nuts and bolts from the swap meet and I was going to dunk it in hydrochloric acid (Muriatic Acid) for a quick bath. But I wasn't sure if the internals were just a metal ball and metal spring, or something the acid would destroy. Anybody ever taken one apart to see what goodies are inside?

thanks,
bob

Primarily a spring and a ball, but not all PCV valves are alike-the ball weight and spring tension varies depending on the engine. Using an incorrect one can really screw things up.
Gary

The Donaldson valves do get gunked up, and are made to be dissassembled, cleaned and put back. If you shake it you should hear some movement inside.
Tim

I was wondering about the valve internals myself just last night.

I took mine apart cleaned the internal single part (a metal poppet) no sign of a spring. I media blasted the external portion of the valve and re-blued it. I then assembled it the same way I took it apart and started to wonder if there should be a spring inside.

I will post a picture of refinished valve tonight. It looks nice but I don't know if it will function correctly. I was going to call Charles later today and ask him about it.

Bert

Hi Bert,

Can you tell me how you "re-blued" it?

thanks,
bob

Hi Bob,

I'll get the name of it tonight and post it along with the picture.

Bert

Bert,

TM9-8030 has a nice diagram of the internals of that valve on page 165. No spring, just that round tapered metal piece (weight) looks to be inside.

Jeff

Bert,

You have a PM.

JJ

Hi Guys,

Jeff....you're right. I pulled one of my PCV valves apart (the Donaldson) and it had the pintle you describe without any spring or check ball. I also took apart two other PCVs that I believe go to the M38 Jeep. That one has a spring and a cone with an orifice at the top of the cone. Both were dirty and needed a good cleaning. I didn't have my camera with me or I would have posted some pics.

regards,
bob

I talked with Charles today and he confirmed what you guys are saying, no spring inside the valve.

Here is a picture of my refinished valve. I used Vans Gun Blue, this is a cold gun blue that if you use it on slightly warmed steel it will look and work as well as salt blue.



Bert